We’re pleased that the story makes the point that foods that are naturally high in fiber — vegetables and fruits, whole grains and beans — are better options, but then we heard something that brought us up short:

So are these fiber-fortified foods actually making you healthier? This question turns out to be one of those places where scientists know a lot less than you may think they do. For example, a lot of people think that fiber will help protect you against colon cancer. But so far, that link is not conclusive.

In this case, it’s “a lot of people” who are right, and NPR who’s … well, not wrong, exactly, but imprecise.

Because the evidence that diets high in fiber can and do protect against colorectal cancer is not only strong, it’s just gotten stronger. And with February being Cancer Prevention Month, it’s a good opportunity to remind people of the hard science showing that they can protect themselves from colorectal cancer. Continue reading →

Last week, at the American Association of Cancer Research (AACR) conference, Dr. Sidney Mirvish presented data from a study which he interprets as strongly suggestive that nitrates are not the agent responsible for higher risk of colon cancer among those whose diets are high in processed meats like hot dogs.

Several in the media and the meat industry are hailing the data as casting doubt on the link between diets high in these foods and colon cancer.

1. Nitrates are only one possible reason for the observed increased risk associated with diets high in processed meats like hot dogs, cold cuts, bacon and sausage. You can find more information in this AICR leaflet.

2. The findings of an individual, as-yet-unpublished study cannot change the clear and convincing evidence that AICR and WCRF have evaluated, which shows that diets featuring processed meat increase colorectal cancer risk.

3. We at AICR welcome the kind of research that seeks to identify the agent or agents in processed meat responsible for the increased risk. Once this study, and others like it, are published and peer-reviewed, they will be added to our Continuous Update Project (CUP) — the largest scientific database on diet and cancer risk in the world — and contribute to our understanding of this issue. They may even ultimately lead to development of processed meats that can be enjoyed without cancer concerns.

4. In the meantime, however, hot dogs and other processed meats remain foods to reserve for special occasions.

Citing the conclusions of WCRF/AICR’s expert report and its recent updates, the pro-vegan advocacy group called the Physician’s Committee for Responsible Medicine (PCRM) has launched a pitched campaign to raise awareness that regular consumption of hot dogs and other processed meats increase risk of colorectal cancer.

Although AICR is not affiliated with PCRM or this campaign, the ad’s claims are based on WCRF/AICR’s Continuous Update Project (CUP), which built and continuously maintains the world’s largest research database on diet, physical activity, weight and cancer. A CUP report on colon cancer risk was released earlier this year, which confirmed the recommendations of an independent, international 21-member expert panel convened by WCRF/AICR.

Among those recommendations: Limit consumption of red meat to 18 ounces per week. But according to the expert panel: “The evidence on processed meat is even more clear-cut than that on red meat, and the data do not show any level of intake that can confidently be shown not to be associated with risk.” Processed meat includes hot dogs, bacon, sausage and lunchmeat.

Specifically, the CUP report concluded that, if a person eats 3.5 ounces (the size of one jumbo hot dog) of processed meat every day, their risk of colorectal cancer will be 36% higher than someone who eats no processed meat. If they eat 7.0 ounces of processed meat every day (49 ounces per week), their risk will be 72% higher, and so on.

That’s why we recommend saving processed meats for special occasions, such as a slice of ham at Easter or a hot dog at a ball game.

But let’s put that extra risk in context.

Take the example of a person eating one jumbo hot dog a day, every day. The fact that his risk for colorectal cancer is 36% higher than someone who doesn’t eat processed meat is a real cause for concern. But note that a 36% increase, while substantial, is not anywhere near the risk associated with cigarette smoking.

Smoking doesn’t simply increase risk for lung cancer, but multiplies a person’s risk by as much as 20 times, according to the CDC.

The increased risk associated with diets high in processed meat is much, much smaller than that. Even a person who eats 7 ounces, day in and day out, increases his risk by 72% — in other words, his risk doesn’t even double, let alone multiply by a factor of 20.

Here’s the bottom line: An occasional hot dog will not cause colon cancer. What the evidence does show, however, is that making processed meats an everyday part of the diet, as many Americans do, poses clear and serious risks. That is why AICR continues to recommend avoiding processed meats.